Are team is having some problems with PWM connections to the motor controller. Does any other teams have this problem and if so how have you gotten around it.
We were thinking about taking the PWM cables and making jumpers for RJ-11. Has anyone done this?
If the problem you are having is merely keeping the straight header on the pins put the connector on and secure with a drop of hot glue.
It’s harmless done with care and easy to undo.
Could you be more specific with your connection issues? As in, are the PWMs not fitting right, are they falling out, not sending a signal, etc.
If your problem is them coming out you can try using gaffers/electrical tape to secure connections together and to motor controllers. We done this with much success over the past few years. For trickier situations where the tape doesn’t hold up you can try hot glue. We had a pwm to one of our shooter jaguars that was always coming loose during aggressive game play that we fixed with hot glue. No issues over this past weekend during some of our roughest play of the year.
Make sure that if you decide to start gluing things to not break Rule 65 from the 2013 game manual which says you cannot glue anything to a motor controller.
<R65>The Driver Station software, cRIO, motor controllers, relay modules, wireless bridge, and batteries shall not be tampered with, modified, or adjusted in any way (tampering includes drilling, cutting, machining, gluing, rewiring, disassembling, etc.), with the following exceptions:
Please note that the Driver Station application is a separate application from the Dashboard. The Driver Station software may not be modified, while teams are expected to customize their Dashboard code.
A. User programmable code in the cRIO may be customized.
B. Dip switches on the cRIO may be set (applies to cRIO-FRC only).
C. Motor controllers may be calibrated as described in owner’s manuals.
D. Fans may be attached to motor controllers and may be powered from the power input terminals.
E. If powering the compressor, the fuse on a Spike H-Bridge Relay may be replaced with a 20A Snap-Action circuit breaker.
F. Wires, cables, and signal lines may be connected via the standard connection points provided on the devices.
G. Fasteners may be used to attach the device to the OPERATOR CONSOLE or ROBOT.
H. Labeling may be applied to indicate device purpose, connectivity, functional performance, etc.
I. Brake/Coast jumpers on motor controllers may be changed from their default location.
J. Limit switch jumpers may be removed from a Jaguar motor controller and a custom limit switch circuit may be substituted.
K. If CAN-bus functionality is used, the Jaguar firmware must be updated as required by FIRST (see Rule R68-D).
L. The First Touch I/O module’s firmware may be modified.
the issue is when connected to the motor controllers we do not always have a good signal. This problem only seems to be an issue when setting up the electrical system. Once we get them all working it is fine. The problem is getting them all working in the first place
What kind of motor controllers are you using, Victor 884, Talon, Tan Jaguar, or something else? Talons take a bit of work to get the PWM connector in the slot, but once it’s in you shouldn’t have any trouble. Victors are notoriously difficult to make a good PWM connection unless you have years of experience doing it right. Jaguars are simple to plug into, but you really need to use the cable retaining hook to keep the connection from coming loose easily.
We are using victors. Any advice on how to make this connection more robust?
Once you get the connector plugged in properly, it’s usually a pretty robust connection. Some teams use a drip of hot glue to prevent it from coming out accidentally. There are also special metal clips you can use that fit under the Victor and reach around the cable to hold the connector in.
Getting it plugged in to begin with is something you’ll just have to get some practice with. Make sure the pins are perfectly straight and get a feel for exactly how they fit the holes hidden at the bottom of the slot. If you don’t do it just right, one or more of the pins can bend aside and miss its target. Once you know how it’s supposed to feel, it will be obvious when it’s done correctly.
A dab of RTV silicone or hot glue is an old and effective solution to the problem of the cables pulling out.
The more common issues is that it is possible to insert the cable and have it give the feel and appearance of being seated, but for the pins to have not actually made it into the sockets. Check the pins very carefully prior to inserting them, looking for bent or short pins. Insert them gently and perfectly straight.
As others have said, hot glue is really awesome for keeping PWM Cables in Victors.
One of the best methods for doing this seems to be something like this:
The method above comes from doing this the wrong way a few times in school. I can remember having to remove hot glued connections a few hours after they were done because no one bothered to check connections prior to gluing. It wasn’t too fun, but not all that bad either.
Please see my post regarding gluing things on electrical devices…
This sounds like some incredibly strong hot glue. Unless you are talking about encasing the connector in glue?
Neat idea. Have you uploaded your design to Thingiverse and share it with the world?
Uploaded! Please let me know your thoughts on its function or any improvements. I can send you cad if you want also.
